Display method for cathode ray tube



Oct. 14, 1969 A. J. CIUFFINI 3,473,075

DISPLAY METHOD FOR CATHODE RAY TUBE Filed Dec. 13, 1966 BY QM? United States Patent 3,473,075 DISPLAY METHOD FOR CATHODE RAY TUBE Anthony J. Ciuflini, Fairport, NY. (39 Havenshire Road, Rochester, N.Y. 14625) Filed Dec. 13, 1966, Ser. No. 601,828 Int. Cl. H01j 31/26 US. Cl. 315 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a cathode ray tube and more particularly to a method of generating distlnct colors by chromatic biasing.

The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

The invention uses the technique of chromatic biasing applied to a ported cathode ray tube and results in the ability of the cathode ray tube to generate several distinct colors which can be used for information coding. This is accomplished with no major changes to existing console circuitry or loss in resolution elements, and it provides for a single gun high resolution color cathode ray tube which can be used in command consoles. Presently there are many cathode ray tube consoles in use that have need for color. The added color supplied by this invention will increase by twofold, the amount of data that can be displayed on a cathode ray tube.

It is therefore an object to provide a method for producing a color cathode ray tube with high resolution.

It is another object to provide a method for producing a color cathode ray tube using single electron gun.

It is still another object to provide a method for producing a color cathode ray tube having three distinct colors for information coding.

These and other advantages, features and objects of the invention will become more apparent from the following description taken in connection with the illustrative embodiment in the accompanying drawing, wherein:

FIGURE 1 shows a ported cathode ray tube with a monochromatic projector; and

FIGURE 2 is a standard chromaticity diagram to aid in understanding the invention.

The invention uses a technique known as chromatic biasing which is the use of a separate monochromatic projectable source. The monochromatic light from this source is mixed with other narrow band light emitting sources and results in the generation of several colors or hues.

Referring to FIGURE 1 there is shown cathode ray tube 11 having electron gun 17 for emitting beam 18 and port 12 for monochromatic projector 13. Monochromatic projector 13 provides a red, blue, green, or any suitable bias on front face 15 of cathode ray tube 11. Since the phosphor layer is slightly difiused, mixing will occur at this plane. If red is chosen as the bias as shown in FIGURE 2 as A, and a green phosphor whose spectral output is that shown at point B, then it is possible to provide a viewer with a yellow and a green which are 3,473,075 Patented Oct. 14, 1969 ice easily recognizable on a red background. If the red bias is chosen to be 5 foot-lamberts and 3 foot-lamberts of green are added by the excitation of the phosphor then point D is obtained which is yellow. If 30 foot-lamberts of green are added then it overrides the red bias and appears as green on the face of the cathode ray tube which is shown as point B.

This scheme will work with any combination of bias and phosphor provided the phosphor is capable of a large change of intensity with a corresponding change in beam current, and that the spectral separation between thebias color and the phosphor color be such that when mixed in appropriate strengths there be two distinct colors possible from the resultant mixtures.

This technique can further be applied to any cathode ray tube that can generate two distinct colors, such as red and blue, from a single phosphor or phosphor layer. In this case the possibility exists for the generation of 5 colors plus white. If red and blue can be generated separately by a single phosphor or phosphor layer, then the simple addition of the two would yield magenta. If green is the bias color as it would have to be in this case then a mixture of green and red would give yellow and a mixture of green and blue would give cyan. By an appropriate mixture of all three, white would be generated. Consequently, this technique gives a red, blue, cyan, yellow, magenta, and white.

While this technique is limited to generation of only a few colors, it is the only technique feasible to generate colors on a high resolution cathode ray tube. Since there are many black and white consoles in use, if each had a two-color capability, then the possibility exists to display twice the amount of information with a few minor changes to each console.

I claim:

1. A method for producing a plurality of colors on a cathode ray tube comprising:

(a) projecting a monochromatic light upon a screen of the cathode ray tube through a port in the tube creating a color bias on the screen;

(b) and varying the intensity of the beam for overriding the color bias forming a resultant color dependent upon the beam intensity and the bias intensity.

2. A method of producing a plurality of colors on a cathode ray tube comprising:

(a) projecting a monochromatic light on the screen of the cathode ray tube through a port in the tube creating a color bias on the screen, the screen being capable of generating two distinct colors from a single phosphor layer;

(b) varying the intensity of the beam for overriding the color bias forming resultant colors dependent upon the beam intensity and theb ias intensity.

References Cited UNITED STATES PATENTS 2,969,474 1/1961 Roberts et al 1785.4 XR

RODNEY D. BENNETT, 1a., Primary Examiner JEFFREY P. MORRIS, Assistant Examiner US. Cl. X.R. 178-5 .4 

